But whether that bar is high enough to change the advice doctors currently give parents with infants who face surgery is a different matter. “We still don’t have enough information to tell parents what they should or shouldn’t do,” he says.

In fact, the FDA convened a committee, on which Flick served, to look into the potentially long lasting effects of anesthesia on young babies. After a review of the literature, which included preliminary results of the current study, the committee members could not come up with definitive guidelines for parents. “We decided the advice was too vague and uninformative,” says Flick.

So, for now, it’s up to individual doctors and parents to decide on the specific risks and benefits of exposing infants to anesthesia. To help clarify the issue, Flick is preparing another study that he hopes will target anesthesia’s effects more accurately; he plans to compare outcomes in children who undergo repair of inguinal hernias (in which parts of the intestines poke through weak portions of the protective abdominal wall) under local anesthesia of the spine to those in children who are put under general anesthesia.

That research may also help highlight the differences in the way local and general anesthesia work. Doctors believe that general anesthetics may accelerate the normal pruning, or death, of neurons that occurs early in life, as babies’ brains, which are constantly forming new connections, feel out which ties will be essential and which are dispensable. Exposure to the agents in anesthesia, for some reason, triggers nerves to die off, which can lead to thinner neural networks and contribute to learning problems later in life.

Flick also notes that the anesthetic drug involved in the current study, which included children born between 1976 and 1982, is no longer used. But that agent is part of a larger family of anesthetics that are common in ORs today and likely have similar effects.

And as frustrating as the findings are, especially for parents who may need to make a decision about whether their child should undergo a surgical procedure, Flick says the results will continue to add to our knowledge about how the youngest brains react to being put to sleep. The more information doctors have, the better advice they will be able to provide to parents.

Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.